Does anyone know about Krell preamp circuts?

How does a Krell KRC,KRC2 etc. pass the single/balanced
signal the the preamp? Most reviews says that they are
Fully balanced yet they have single ended inputs.
I'm still confused about this can anyone answer?
The single ended inputs have a phase splitter so the input gets turned into a balanced (+phase, -phase & ground) signal for the gain and attenuation circuts.